Method and apparatus for producing combustible fluid

ABSTRACT

This invention relates to a method and apparatus for producing combustible fluid at an efficiency rate of above 65%. The apparatus  10  comprises an electrolysing cell  12  for electrolysing the aqueous electrolytic solution; a separator  16  where the combustible fluid and the solution is separated; a power supply  14  for supplying a DC voltage of from 1 V to 6 V; and a pump for circulating the solution through the apparatus  10.  The electrolysing cell  12  includes a first electrode  18  and a second electrode  20  spaced from the first electrode  18  and a plurality of intermediate electrodes  22  disposed between the first and second electrodes  18  and  20  respectively. The power supply  14  applies the DC voltage across the electrodes  18, 20  and  22  to electrolyse the solution, while the solution is circulated through the apparatus  10.

INTRODUCTION AND BACKGROUND TO THE INVENTION

This invention relates to a method and apparatus for producing combustible fluid. More particularly this invention relates to a method and apparatus for producing hydrogen and oxygen through the electrolysis of an aqueous electrolytic solution.

In this specification, the term “combustible fluid” includes within its scope combustible gas containing predominantly hydrogen and oxygen.

U.S. Pat. No. 4,379,043 discloses an apparatus for decomposing water and producing detonating gas by electrolysis. The apparatus includes a plurality of annular carbon electrodes which are arranged concentrically about a common vertical axis. The annular electrodes are perforated and have upper and lower ends, the lower ends being positioned adjacent to sealing and insulating elements in order to form a plurality of concentrically-arranged cells for containing an electrolyte, such as water. A solid cylindrical carbon electrode is positioned within the smallest concentric electrode and along the common axis. A voltage of 12 V and current of 80 A are applied to the apparatus by a direct current source in order to evolve the detonating gas from the electrolyte in the cells by electrolysis.

A disadvantage of the above described known apparatus is that the ratio between power consumed and combustible fluid produced is unfavourable, so that its efficiency is relative low, i.e. the energy produced is less than 65% of the energy consumed in the process.

OBJECT OF THE INVENTION

It is accordingly an object of the present invention to provide an alternative method and apparatus for the production of combustible fluid overcoming the above disadvantage by producing combustible fluid at relatively higher efficiency rates, i.e. the energy produced is substantially more than 65% of the energy consumed in the process.

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided a method for the production of combustible fluid from an aqueous electrolytic solution including the steps of:

-   -   providing an aqueous electrolytic solution;     -   providing an electrolysing cell having at least two spaced apart         electrodes defining a passage between them; and     -   passing the solution along the passage whilst applying a DC         voltage across the electrodes to electrolyse the solution, the         voltage being in the range of from 1 V to 6 V.

The two spaced apart electrodes may be a first outer electrode and a second inner electrode, and the method may include the further step of providing a plurality of intermediate electrodes disposed between the first and second electrodes, the arrangement being such that a plurality of passages, each having an inlet and an outlet, are defined between the electrodes, and the step of passing the solution along the passage may include the further step of passing the solution along the passages whilst applying the voltage across the electrodes.

The step of applying the DC voltage across the electrodes may include the step of applying a DC voltage in the range of from 2 V to 4 V, preferably in the range of from 2.75 V to 3.25 V across the electrodes.

The step of applying the DC voltage across the electrodes may include the further step of applying a pulsed DC voltage across the electrodes.

The step of applying the pulsed DC voltage across the electrodes may include the further step of applying a pulsed DC voltage having a duty cycle of from 10% to 90% and a frequency of from 5 kHz to 20 kHz.

The voltage may be pulsed at a duty cycle of from 30% to 70%, preferably from 40% to 60%.

The voltage may be pulsed at a frequency of from 10 kHz to 15 kHz, preferably 13 kHz.

The solution may be passed continuously along the passages from the inlets to the outlets.

In passing the solution along the passages, the solution may be pumped from the inlets to the outlets of the passages.

The combustible fluid may be produced on the surface of the electrodes and in between the electrodes in the passages between the electrodes, in the form of gas bubbles and the step of electrolysing the solution may include the further step of physically removing the gas bubbles from the surfaces of the electrodes and from the passages, and moving the bubbles towards the outlets of the passages by the stream of the solution flowing along the passages.

The step of providing the aqueous electrolytic solution may include the further step of providing a sodium hydroxide solution in water of from 1% to 5% on a mass per mass basis, preferably a 3% sodium hydroxide solution in water.

According to a second aspect of the invention there is provided apparatus for the production of combustible fluid from an aqueous electrolytic solution comprising:

-   -   an electrolysing cell for electrolysing the aqueous electrolytic         solution, the electrolysing cell having a first electrode and a         second electrode spaced from the first electrode and a passage         defined between the electrodes, the passage having an inlet and         an outlet;     -   a circulating means for circulating the solution from the inlet,         along the passage, to the outlet and back to the inlet via a         separate passage; and     -   a power supply for applying a DC voltage across the electrodes         to electrolyse the solution whilst passing along the passage,         the voltage being in the range of from 1 V to 6 V.

The DC voltage applied across the electrodes may preferably be in the range of from 2 V to 4 V, more preferably in the range of from 2.75 V to 3.25 V, most preferably, the voltage may be in the range of from 2.85 V to 2.95 V.

The apparatus may include a pulsing means for applying a pulsed voltage across the electrodes.

The pulsing means may be adapted to apply the pulsed DC voltage at a duty cycle of from 10% to 90% and a frequency of from 5 kHz to 20 kHz.

More particularly, the pulsing means may be adapted to apply the pulsed DC voltage at a duty cycle of from 30% to 70%, preferably from 40% to 60%.

Further more particularly, the pulsing means may be adapted to pulse the DC voltage at a frequency of from 10 kHz to 15 kHz, preferably 13 kHz.

The electrolytic solution may be in the form of a sodium hydroxide solution in water.

The electrolytic solution may be a sodium hydroxide solution in water of from 1% to 5% on a mass per mass basis, preferably a 3% sodium hydroxide solution in water.

The electrodes may be tubular and elongate and may be arranged concentrically with each other.

The first electrode may be an outer electrode, with the second electrode being an inner electrode disposed within the outer electrode.

A plurality of intermediate tubular concentrically arranged electrodes may be disposed between the first and second electrodes, the arrangement being such that a plurality of passages, each having an inlet and an outlet, and along which the solution may be circulated, are defined between adjacent electrodes.

The longitudinal axes of the electrodes may extend vertically so that the passages also extend vertically and the inlets may be provided towards the lower end of the electrolysing cell and the outlets may be provided towards the upper end of the electrolysing cell.

The inlet of each of the passages may be defined by the lower ends of the electrodes and the outlet of each of the passages may be defined by the upper ends of the electrodes.

The opposite ends of the electrodes may be interposed between isolators.

The electrodes may further be electrically connected to two conductors, the arrangement being such that the electrodes are connected in a parallel configuration in that every second electrode may be connected to an upper conductor, which is electrically connected to one pole of the power supply and the other electrodes may be connected to a lower conductor, which is electrically connected to an opposite pole of the power supply.

Alternatively, the electrodes may be connected in a series configuration with the plurality of intermediate tubular concentrically arranged electrodes being floating electrodes disposed between the first and second electrodes, with the first electrode having an opposite polarity to the second electrode.

The spacing between the electrodes may be from 1 mm to 8 mm.

In the case where the electrodes are connected in the parallel configuration, the spacing between the electrodes may be the same between all adjacent electrodes.

Alternatively, in the case where the electrodes are in the series configuration, the spacing between adjacent electrodes may increase radially outwardly.

The electrodes may be made from conductive material and may be elongate in nature, the first outer electrode generally having an opposite polarity to the second inner electrode.

The electrodes may be made from conductive material, more specifically the electrodes may be made of grade 316 stainless steel.

The electrolysing cell may be completely filled with the aqueous electrolytic solution, such that the electrodes are submerged in the solution.

The circulating means may be in the form of a pump and may continuously pump the solution in an upwardly direction from the lower inlet of the passages to the upper outlet thereof.

The circulating means may be connected to the electrolysing cell via the separate passage, so that the solution is pumped from the inlet, along the passages, to the outlet and back to the inlet via the separate passage.

According to a third aspect of the invention there is provided an internal combustion engine used in conjunction with the apparatus.

According to a fourth aspect of the invention there is provided a fuel cell used in conjunction with the apparatus.

According to a fifth aspect of the invention there is provided a torch for cutting or welding used in conjunction with the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described further by way of a non-limiting example with reference to the accompanying drawings wherein:

FIG. 1 is a schematic representation of an apparatus 10 according to a preferred embodiment of the invention for the production of combustible fluid from an aqueous electrolytic solution, the apparatus including an electrolysing cell 12, a power supply 14 and a separator 16;

FIG. 2 is a longitudinal-sectional side view of the electrolysing cell 12 and the separator 16 shown schematically in FIG. 1;

FIG. 3A is a perspective view from one end of electrodes 18, 20 and 22 of the electrolysing cell 12;

FIG. 3B is a perspective view from another end of electrodes 18, 20 and 22 of the electrolysing cell 12

FIG. 4 is a view from below of an upper isolator 25;

FIG. 5 is a view from above of a lower isolator 23;

FIG. 6 is a graph showing current measurements and average current calculated as drawn by the electrolysing cell 12 in operation;

FIG. 7 is a graph showing voltage measurements and average voltage as used by the electrolysing cell 12;

FIG. 8 is a is a graph showing power and average power calculated and as consumed by the electrolysing cell 12;

FIG. 9 is another graph showing voltage measurements for voltage drawn by the cell 12; and

FIG. 10 is another graph showing current measurements for current drawn by the cell 12.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Referring to FIG. 1, an apparatus according to a preferred embodiment of the invention for producing combustible fluid from an aqueous electrolytic solution is generally designated by reference numeral 10.

The apparatus 10 comprises an electrolysing cell 12 for electrolysing the aqueous electrolytic solution; a power supply 14 for supplying a DC voltage; and a separator 16 wherein the combustible fluid is separated from the aqueous electrolytic solution.

Referring further to FIGS. 2 to 5, the electrolysing cell 12 includes a first electrode 18 and a second electrode 20 spaced from the first electrode 18. The first electrode 18 is an outer electrode, with the second electrode 20 being an inner electrode disposed within the outer electrode 18. Intermediate electrodes 22.1 to 22.6 (collectively referred to as 22) are disposed between the first and second electrodes 18 and 20 respectively.

The electrodes 18, 20 and 22 are tubular, elongate and made from grade 316 stainless steel and are arranged concentrically with each other with their longitudinal axes extending vertically, as shown in detail in FIG. 3. The opposite ends of the electrodes 18, 20 and 22 are interposed between a lower inlet isolator 23 and an upper outlet isolator 25. The electrodes are further electrically connected in a parallel fashion with to an upper conductor 26 and a lower conductor 28. The arrangement is such that every second electrode 22.1, 22.3. 22.5 and 18 is connected to the upper conductor 26 and the other electrodes 20, 22.2, 22.4 and 22.6 are connected to the lower conductor 28. The upper conductor 26, and thus the electrodes 22.1, 22.3, 22.5 and 18, are electrically connected to one pole of the power supply 14, in this case to the negative pole, and the lower conductor 28, and thus the electrodes 20, 22.2, 22.4 and 22.6, are electrically connected to an opposite pole of the power supply 14, in this case to the positive pole.

The electrodes 18, 20 and 22 could alternatively be connected in a series configuration with the intermediate electrodes 22 being floating electrodes disposed between the first and second electrodes 18 and 20. The first electrode 18 would have an opposite polarity to the second electrode 20.

The inlet and outlet isolators 23 and 25 are made from a non-conductive material, such as Perspex. The isolators 23 and 25 each define a plurality of grooves 23.1 and 25.1, shown in FIGS. 4 and 5, wherein the electrodes 18, 20 and 22 are located. The upper isolator 25 further defines outlet passages 25.2 and the lower isolator defines an inlet passage 23.2.

The electrodes 18, 20 and 22 are located in the grooves 23.1 and 25.1 of the isolators 23 and 25 so as to retain the electrodes 18, 20 and 22 in position and at a distance of from 4 mm to 8 mm apart. The length of the electrodes 18, 20 and 22 is 350 mm each. Electrode 20 has a diameter of 25.4 mm, electrode 22.1 has a diameter of 38.1 mm, electrode 22.2 has a diameter of 50.8 mm, electrode 22.3 has a diameter of 63.5 mm, electrode 22.4 has a diameter of 76.2 mm, electrode 22.5 has a diameter of 88.9 mm, electrode 22.6 has a diameter of 101.6 mm, and electrode 18 has a diameter of 114.3 mm. Therefore, the distance between electrodes 20 and 22.1 is 4.85 mm, between electrodes 22.1 and 22.2 is 4.85 mm, between electrodes 22.2 and 22.3 is 4.85 mm, between electrodes 22.3 and 22.4 is 4.85 mm, between electrodes 22.4 and 22.5 is 4.85 mm, between electrodes 22.5 and 22.6 is 4.85 mm, and between electrodes 22.6 and 18 is 4.85 mm. Furthermore, the conductive areas of the electrodes (without subtracting cut-outs, variance between inner and outer diameters of the 1.5 mm thick electrodes, and holes defined in the electrodes) are as follows: electrode 20 has a circumference of 79.83 mm and a single side area of 0.0279 m²; electrode 22.1 has a circumference of 119.74 mm and a double side area of 0.0838 m²; electrode 22.2 has a circumference of 159.66 mm and a double side area of 0.1118 m²; electrode 22.3 has a circumference of 199.57 mm and a double side area of 0.1397 m²; electrode 22.4 has a circumference of 239.49 mm and a double side area of 0.1676 m²; electrode 22.5 has a circumference of 279.40 mm and a double side area of 0.1956 m², electrode 22.6 has a circumference of 319.31 mm and a double side area of 0.2235 m²; and electrode 18 has an inside circumference of 349.80 mm and a single side area of 0.1224 m². The conductive areas of the electrodes therefore amount to 1.0723 m².

In the case where the electrodes 18, 20 and 22 are connected in the series configuration, the spacing between adjacent electrodes 18, 20 and 22 increases as they are located further from the second electrode 20 radially outwardly. A plurality of passages 30 are defined by the electrodes 18, 20 and 22, the arrangement being such that the electrolytic solution contained within the electrolytic cell 12 can freely pass along said passages 30. The passages 30 each have a lower inlet 29 defined by the lower ends of the electrodes 18, 20 and 22 and an upper outlet 31 defined by the upper ends of the electrodes 18, 20 and 22, and the solution passes from the lower inlets 29 to the upper outlets 31 along the passages 30.

The electrolysing cell 12 is provided with a first inlet 32, located towards a lower end of the electrolysing cell 12 for allowing electrolytic solution to pass into the electrolysing cell 12 via the inlet passage 23.2 of the lower isolator 23. The electrolysing cell 12 is further provided with a first outlet 34, located towards an upper end of the electrolysing cell 12, for allowing solution containing combustible fluid to flow from the passages 30 through the outlet passages 25.2 to a chamber 33. The combustible fluid produced by the apparatus 10, in use, thus flows from the electrolysing cell 12 via the first outlet 34 to the separator 16, having a second inlet 35 connected in fluid flow communication with the electrolysing cell 12 via the first outlet 34.

In passing the solution along the passages form the first inlet 32 via the inlet passage 23.2 of the lower isolator 23, the solution moves in a swirling motion. This motion is initiated by the triangular shape of the inlet passage 23.2. The swirling motion assists with the even flow of the solution along the passages and over the surfaces of the electrodes 18, 20 and 22, thus avoiding cold spots, where the concentration of combustible fluid will reduce conductivity and thus current density, between the electrodes. The triangular shape of the inlet passage 23.2 further assists in the flow rate of the solution being proportional to the diameters of the passages 30. Equal volumetric flow of the solution over the surfaces of the electrodes 18, 20 and 22 is thus achieved to maintain an equal current density between all the electrodes.

In the separator 16, the solution is separated into combustible fluid and its solution components, and the fluid flows from the separator 16 via a fluid outlet 36, located towards the top of the separator 16. The separator 16 is further provided with a second outlet 37, located towards the lower end thereof. The second outlet 37 is connected to the first inlet 32 via a separate passage to a circulating means in the form of a pump (not shown), such that the solution is continuously circulated through the apparatus 10 and along the passages 30 in an upwardly direction, as indicated by the arrows in FIG. 2. The pump circulates the solution through the apparatus 10 at a rate of approximately 100 litres per hour. The pump is a 12 V, 600 mA pump.

The power supply 14 includes a pulsing means and applies a pulsed DC voltage of from 2 V to 4 V, specifically in the order of 2.85 V, at a frequency of from 5 kHz to 20 kHz, specifically 13 kHz, and at a duty cycle of from 10% to 90%, specifically 60%, across the electrodes 18, 20 and 22 of the electrolysing cell 12. During operation, the power supply 14 is connected to the upper and lower conductors 26 and 28, such that the electrodes 22.1, 22.3, 22.5 and 18 are connected to the negative pole of the power supply 14 and electrodes 20, 22.2, 22.4 and 22.6 to the positive pole of the power supply 14, or vice versa.

The electrolytic solution is prepared from 99% pure sodium hydroxide and is in the form of a 3% sodium hydroxide solution in water on a mass per mass basis. However, there are numerous other electrolytic solutions known in the art that would also suffice.

In use, the electrolysing cell 12 and the passages 30 are filled completely with the electrolytic solution, such that the electrodes 18, 20 and 22 are submerged in the solution, and the separator 16 is filled approximately halfway with the solution. The pump continuously circulates the solution to pass along the passages 30 of the electrolysing cell 12 and to the separator 16. Only when the solution is circulated along the passages 30, is the power supply 14 switched on to apply the pulsed DC voltage across the electrodes. Electrolysis takes place in the electrolysing cell 12. The solution containing the fluid, which is in the form of gas bubbles formed on the surfaces of the electrodes 18, 20 and 22 and between the electrodes 18, 20 and 22, is physically removed from the surfaces of the electrodes 18, 20 and 22 and from the passages 30 towards the upper outlets 31 of the passages 30 by the stream of solution flowing along the passages 30. The fluid then flows through the outlet passages 25.2 of the isolator 25 and into the chamber 33. From the cell 12 the solution flows to the separator 16, via the first outlet 34 to the second inlet 35 of the separator, where the combustible fluid is separated from the solution. In the separator 16 the fluid flows out of the separator 16 via the fluid outlet 36 and the solution is pumped via the second outlet 37 to the first inlet 32.

From time to time the level of the solution in the separator 16 is topped up, so that the separator is filled to approximately half of its volume.

EXAMPLE 1

An experiment was conducted to measure the power dissipated and combustible fluid produced by the apparatus 10 during electrolysis of the electrolytic solution as described above.

Results 1

A 6 V power supply was connected to the apparatus 10 to supply a pulsed voltage at a frequency of 15 kHz at a duty cycle of 56.5%. The current and average current drawn by the cell 12, the voltage and average voltage used by the cell 12 and the power and average power dissipated by the cell, was measured at the battery terminals. It was calculated that the average power dissipated by the cell 12 was 218 W. FIGS. 6 to 8 show the graphs of current, voltage and power respectively, obtained from the measurements taken.

EXAMPLE 2

In another experiment conducted to measure the time averaged power dissipated by the cell and the pump during the electrolysis process. The following results were obtained.

Results 2

A 6 V power supply was connected to the apparatus 10 to supply a pulsed voltage at a frequency of 15 kHz at a duty cycle of approximately 60%. The current and average current drawn by the cell 12, the voltage and average voltage used by the cell 12 and the power and time averaged power dissipated by the cell, was measured at the battery terminals. It was calculated that the average power dissipated by the cell 12 was 157.73 W and the average power dissipated by pump was 6.74 W. The time taken to generate 250 ml combustible fluid was 10 seconds and combustible fluid was thus produce at a rate of 1.51 litres per minute (l/min), which is 9.12 litres per kilowatt minute (l/kWmin).

EXAMPLE 3

In another experiment conducted to measure the power consumed by the cell, the following results were obtained.

Results 3

The power supply was connected to the apparatus 10 to supply a pulsed voltage at a frequency of 15 kHz at a duty cycle of 44%. The average voltage drawn by the cell 12 was 2.88 V, as depicted in the graph of FIG. 9, and the average current drawn by the cell 12 was 104 A, as depicted in FIG. 10. From these measurements, it was calculated that the average power dissipated by the cell 12 was 299 W.

The applicant has found that the apparatus 10 performs far more superior than the prior art since it utilises relatively low voltage and current and is relatively much more efficient in the production of combustible fluid than any of the prior art apparatus hitherto known to the public. The apparatus 10 is furthermore compact and relatively easy to operate compared to the prior art.

The fluid may be used as a source of energy in any number of applications, such as for generating heat or electricity, welding machines, rocket or jet engines, or for running an internal combustion engine of a vehicle or a fuel cell vehicle.

It will be appreciated that variations in detail are possible with a method and apparatus for producing combustible fluid according to the invention without departing from the scope of the appended claims. For example, the electrodes could also be arranged horizontally with an inlet towards one end of the cell and the outlet towards the other end of the cell. 

1. A method for the production of combustible fluid from an aqueous electrolytic solution including the steps of: providing an aqueous electrolytic solution; providing an electrolysing cell having at least two spaced apart electrodes defining a passage between them; and passing the solution along the passage whilst applying a DC voltage across the electrodes to electrolyse the solution, the voltage being in the range of from 1 V to 6 V.
 2. A method according to claim 1 wherein the two spaced apart electrodes is a first outer electrode and a second inner electrode, and the method includes the further step of providing a plurality of intermediate electrodes disposed between the first and second electrodes, the arrangement being such that a plurality of passages, each having an inlet and an outlet, are defined between the electrodes, and the step of passing the solution along the passage may include the further step of passing the solution along the passages whilst applying the voltage across the electrodes.
 3. A method according to claim 1 wherein the step of applying the DC voltage across the electrodes includes the step of applying the DC voltage in the range of from 2 V to 4 V across the electrodes.
 4. A method according to claim 3 wherein the step of applying the DC voltage across the electrodes includes the step of applying the DC voltage in the range of from 2.75 V to 3.25 V across the electrodes.
 5. A method according to claim 1 wherein the step of applying the DC voltage across the electrodes include the further step of applying a pulsed DC voltage across the electrodes.
 6. A method according to claim 5 wherein the step of applying the pulsed DC voltage across the electrodes includes the further step of applying a pulsed DC voltage having a duty cycle of from 10% to 90% and a frequency of from 5 kHz to 20 kHz.
 7. A method according to claim 6 wherein the voltage is pulsed at a duty cycle of from 30% to 70%.
 8. A method according to claim 7 wherein the voltage is pulsed at a duty cycle of from 40% to 60%.
 9. A method according to claim 5 wherein the voltage is pulsed at a frequency of from 10 kHz to 15 kHz.
 10. A method according to claim 9 wherein the voltage is pulsed at a frequency of 13 kHz.
 11. A method according to claim 2 wherein the solution is passed continuously along the passages from the inlets to the outlets, by being pumped from the inlets, along the passage, to the outlets and back to the inlets via a separate passage.
 12. A method according to claim 11 wherein the combustible fluid is produced on the surface of the electrodes and in between the electrodes in the passages between the electrodes, in the form of gas bubbles and the step of electrolysing the solution includes the further step of removing the gas bubbles from the surfaces of the electrodes and from the passages, and moving the bubbles towards the outlets of the passages by the stream of the solution flowing along the passages.
 13. A method according to claim 1 wherein the step of providing the aqueous electrolytic solution includes the further step of providing a sodium hydroxide solution in water of from 1% to 5% on a mass per mass basis.
 14. A method according to claim 13 wherein the step of providing the aqueous electrolytic solution includes the further step of providing a 3% sodium hydroxide solution in water.
 15. Apparatus for the production of combustible fluid from an aqueous electrolytic solution comprising: an electrolysing cell for electrolysing the aqueous electrolytic solution, the electrolysing cell having a first electrode and a second electrode spaced from the first electrode and a passage defined between the electrodes, the passage having an inlet and an outlet; a circulating means for circulating the solution from the inlet, along the passage, to the outlet and back to the inlet via a separate passage; and a power supply for applying a DC voltage across the electrodes to electrolyse the solution whilst passing along the passage, the voltage being in the range of from 1 V to 6 V.
 16. Apparatus according to claim 15 wherein the DC voltage applied across the electrodes is in the range of from 2 V to 4 V.
 17. Apparatus according to claim 16 wherein the DC voltage applied across the electrodes is in the range of from 2.75 V to 3.25 V.
 18. Apparatus according to claim 17 wherein the DC voltage applied across the electrodes is in the range of from 2.85 V to 2.95 V.
 19. Apparatus according to claim 15 which includes a pulsing means for applying a pulsed voltage across the electrodes.
 20. Apparatus according to claim 19 wherein the pulsing means is adapted to apply the pulsed DC voltage at a duty cycle of from 10% to 90% and a frequency of from 5 kHz to 20 kHz.
 21. Apparatus according to claim 20 wherein the pulsing means is adapted to apply the pulsed DC voltage at a duty cycle of from 30% to 70%.
 22. Apparatus according to claim 21 wherein the pulsing means is adapted to apply the pulsed DC voltage at a duty cycle of from 40% to 60%.
 23. Apparatus according to claim 22 wherein the pulsing means is adapted to apply the pulsed DC voltage at a duty cycle of from 10 kHz to 15 kHz.
 24. Apparatus according to claim 23 wherein the pulsing means is adapted to apply the pulsed DC voltage at a duty cycle of 13 kHz.
 25. Apparatus according to claim 15 wherein the electrolytic solution is in the form of a sodium hydroxide solution in water.
 26. Apparatus according to claim 25 wherein the electrolytic solution is a sodium hydroxide solution in water of from 1% to 5% on a mass per mass basis.
 27. Apparatus according to claim 26 wherein the electrolytic solution is a 3% sodium hydroxide solution in water.
 28. Apparatus according to claim 15 wherein the electrodes are tubular and elongate and are arranged concentrically with each other, with the first electrode being an outer electrode and the second electrode being an inner electrode disposed within the outer electrode.
 29. Apparatus according to claim 28 wherein a plurality of intermediate tubular concentrically arranged electrodes are disposed between the first and second electrodes, the arrangement being such that a plurality of passages, each having an inlet and an outlet, and along which the solution is circulated, are defined between adjacent electrodes.
 30. Apparatus according to claim 29 wherein the longitudinal axes of the electrodes extend vertically so that the passages also extend vertically and the inlets are provided towards the lower end of the electrolysing cell and the outlets are provided towards the upper end of the electrolysing cell.
 31. Apparatus according to claim 30 wherein the inlet of each of the passages is defined by the lower ends of the electrodes and the outlet of each of the passages is defined by the upper ends of the electrodes.
 32. Apparatus according to claim 31 wherein opposite ends of the electrodes are interposed between isolators.
 33. Apparatus according to claim 32 wherein the electrodes are further electrically connected to two conductors, the arrangement being such that the electrodes are connected in a parallel configuration in that every second electrode is connected to an upper conductor, which is electrically connected to one pole of the power supply and the other electrodes are connected to a lower conductor, which is electrically connected to an opposite pole of the power supply.
 34. Apparatus according to claim 32 wherein the electrodes are connected in a series configuration with the plurality of intermediate tubular concentrically arranged electrodes being floating electrodes disposed between the first and second electrodes, with the first electrode having an opposite polarity to the second electrode.
 35. Apparatus according to claim 29 wherein the spacing between the electrodes is from 1 mm to 8 mm.
 36. Apparatus according to claim 34 wherein, in the case where the electrodes are connected in the parallel configuration, the spacing between the electrodes is the same between all adjacent electrodes.
 37. Apparatus according to claim 34 wherein, in the case where the electrodes are in the series configuration, the spacing between adjacent electrodes increases radially outwardly.
 38. Apparatus according to claim 28 wherein the electrodes are made of grade 316 stainless steel and the first outer electrode has an opposite polarity to the second inner electrode.
 39. Apparatus according to claim 29 wherein the electrolysing cell is completely filled with the aqueous electrolytic solution, such that the electrodes are submerged in the solution.
 40. Apparatus according to claim 39 wherein the circulating means is in the form of a pump and which continuously pumps the solution in an upwardly direction from the lower inlet of the passages to the upper outlet thereof and back to the lower inlet via the separate passage.
 41. An internal combustion engine used in conjunction with an apparatus according to claim
 15. 42. A fuel cell used in conjunction with an apparatus according to claim
 15. 43. A cutting torch used in conjunction with an apparatus according to claim
 15. 44. A welding torch used in conjunction with an apparatus according to claim
 15. 45. A method for the production of combustible fluid from an aqueous electrolytic solution substantially as herein described with reference to the accompanying drawings.
 46. (canceled) 